1. Field of the Invention
The present invention relates to a so-called head-mounted type of display apparatus (head-mounted display) which permits a user to view a display image with the display apparatus being mounted on a predetermined portion of the user, such as the head or the face.
2. Description of Related Art
Conventionally, this kind of display apparatus has not had the function of informing a user himself/herself how long the user has been using the display apparatus.
In recent years, this kind of display apparatus has been used in more and more applications which enable users to view images or the like. Computer games are the most popular of such applications. Unlike normal television screens, this kind of display apparatus can easily create a closed space, so that a user can be more deeply immersed in the world of a game. Furthermore, such a display apparatus is provided with a head detecting device for detecting the motion of the head of the user, and can realize virtual reality (VR) by varying a display image according to the detection value of the head detecting device. This kind of display apparatus can also be used as a computer display. The use of the display apparatus enables a user to operate a computer anywhere without the need to use a large CRT display and without worrying whether someone is peeping at the user""s display.
This kind of display apparatus using a small liquid crystal display panel is arranged as shown in FIG. 1. In the arrangement shown in FIG. 1, light emitted from a backlight 1902 passes through a display 1901 such as a liquid crystal display panel, and is made incident on an entrance surface 1900a of an optical element 1900. The light passing through the entrance surface 1900a is made incident on a reflecting surface 1900b of the optical element 1900 at an angle of incidence not less than a critical angle and is totally reflected from the reflecting surface 1900b toward a total reflection surface 1900c of the optical element 1900. The light is again totally reflected by the total reflection surface 1900c and is made incident on the reflecting surface 1900b at an angle of incidence not greater than the critical angle. The light incident at the angle of incidence not greater than the critical angle is conducted to a pupil 1908 of a user and an image is displayed by the display 1901, so that the user can view the displayed image.
However, the above-described conventional apparatus has the problem that a user may continuously use the display apparatus over a long time without noticing the lapse of use time.
In addition, the conventional display which is used as display means for a game or a computer has the problem that a user often tends to immerse himself/herself in a display picture and continuously wear the display apparatus over a long time, as well as the problem that it is troublesome for the user to frequently put on and take off the display apparatus.
Furthermore, regarding the display apparatus shown in FIG. 1, the user may continuously use the display apparatus over a long time without noticing the lapse of use time. Although there is a method of displaying clock information in the display 1901 to prevent this problem, this method may not agree with the intention of the user, because the display apparatus is intended to create virtual reality.
It is, therefore, an object of the present invention to provide a display apparatus capable of solving the above-described problems.
Another object of the present invention is to provide a display apparatus capable of preventing a user from continuously using the display apparatus over a long time without noticing elapsed time.
To achieve the above objects, according to one aspect of the present invention, there is provided a display apparatus which visibly displays a video image represented by an input video signal, in the state of being mounted on a predetermined portion of a user, and which comprises video image displaying means for displaying the video image, video image display driving means for causing the video image displaying means to display the video image, optical system means for conducting the video image displayed by the video image displaying means to a pupil of the user, use time setting means for setting a use time, the use time setting means being capable of setting an arbitrary time, and informing means for measuring a continuous use time of the display apparatus and, immediately before an end of the use time set by the use time setting means, informing the user that the use time will end shortly, or, immediately after the end of the use time set by the use time setting means, informing the user that the use time has ended.
Another object of the present invention is to provide a display apparatus which a user can continuously use for only a required time while recognizing the lapse of time.
To achieve the above object, according to another aspect of the present invention, there is provided a display apparatus which visibly displays a video image represented by an input video signal, in the state of being mounted on a predetermined portion of a user, and which comprises video image displaying means for displaying the video image, video image display driving means for causing the video image displaying means to display the video image, optical system means for conducting the video image displayed by the video image displaying means to a pupil of the user, use time setting means for setting a use time, the use time setting means being capable of setting an arbitrary time, and control means arranged to measure a continuous use time of the display apparatus and, immediately before an end of the use time set by the use time setting means, inform the user that the use time will end shortly, or, immediately after the end of the use time set by the use time setting means, inform the user that the use time has ended, and arranged to permit resetting for extending the use time set by the use time setting means according to a request of the user.
Another object of the present invention is to provide a display apparatus which does not at all force a user to perform the complicated operation of newly setting use time each time the user uses the display apparatus, and also which enables use time to be set to an arbitrary time according to the request of the user.
To achieve the above object, according to another aspect of the present invention, there is provided a display apparatus which visibly displays a video image represented by an input video signal, in the state of being mounted on a predetermined portion of a user, and which comprises video image displaying means for displaying the video image, video image display driving means for causing the video image displaying means to display the video image, optical system means for conducting the video image displayed by the video image displaying means to a pupil of the user, use time setting means for setting a use time, the use time setting means being capable of setting an arbitrary time, use time indicating means for indicating a predetermined use time which is preset, and informing means for starting measurement of a continuous use time of the display apparatus when a power source thereof is turned on, and, immediately before an end of the predetermined use time indicated by the use time indicating means, informing the user that the use time will end shortly, or, immediately after the end of the predetermined use time indicated by the use time indicating means, informing the user that the use time has ended, the informing means, if the use time is set by the use time setting means after the power source of the display apparatus is turned on, informing the user that the use time will end shortly, immediately before an end of the use time set by the use time setting means, or informing the user that the use time has ended, immediately after the end of the use time set by the use time setting means.
Another object of the present invention is to provide a display apparatus which can prevent a user from continuously using the display apparatus for a long time.
To achieve the above object, according to another aspect of the present invention, there is provided a display apparatus which visibly displays a video image represented by an input video signal, in the state of being mounted on a predetermined portion of a user, and which comprises video image displaying means for displaying the video image, video image display driving means for causing the video image displaying means to display the video image, optical system means for conducting the video image displayed by the video image displaying means to a pupil of the user, time measuring means for measuring time which elapses after a predetermined timing, and outputting an information signal relative to the measured time, and display operation control means for controlling a state of display of the video image in the video image displaying means according to a content represented by the information signal outputted from the time measuring means.
Yet another object of the present invention is to provide a display apparatus which can inform a user of the elapsed time of continuous use and warn the user of continuous long-time use.
To achieve the above object, according to another aspect of the present invention, there is provided a display apparatus which visibly displays a video image represented by an input video signal, in the state of being mounted on a predetermined portion of a user, and which comprises video image displaying means having a plurality of different kinds of video image display modes, for displaying the video image in accordance with any of the video image display modes, video image display driving means for causing the video image displaying means to display the video image, optical system means for conducting the video image displayed by the video image displaying means to a pupil of the user, use time setting means for setting a use time, the use time setting means being capable of setting an arbitrary time, and display mode setting means for setting a video image display mode in the video image displaying means according to a state of lapse of the use time set by the use time setting means.